Aurelio Bay Institut de Physique des Hautes Energies [email protected] July 13-25, 2000,...
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Transcript of Aurelio Bay Institut de Physique des Hautes Energies [email protected] July 13-25, 2000,...
Aurelio BayInstitut de Physiquedes Hautes Energies
July 13-25, 2000, Hanoi, Vietnam
SM
~Vub
from BXu+l
from m:
B0B0
B0
J Ks
W Wt
t
CP Asym ~ sin[2(new )]
t
d
b
tW W
b
d
~
~Vtd
The Unitary TriangleThe Unitary Triangle
Im
Re
SM + New FCNC
~Vub
from BXu+l
from m:+rnew
new
B0B0
B0
J Ks
W Wt
t
CP Asym ~ sin(2(new))
t
d
b
tW W
b
d
~
d
b
b
dNEWFCNC
Unchanged
rnew
NEW
The Unitary TriangleThe Unitary Triangle
Im
Re
from Bd D*-n+, D*+n-, etc.
Idem with Bs decays:Idem with Bs decays:
snew from CP in Bs J
snew from CP in Bs Ds
K, Ds
K
compare the two determinations(then combine them)
Bd D*nvs Bd D*n
Bd D*n vs Bd D*n
From 2(new) +
CP in BJ/Ks ~ 2(+new)
We want to measure , we need to select hadronic decay channels,
we want to study the Bs system, have K/ separation, access to Br < 10….
• BABAR, BELLE, CLEO-III, CDF, D0, HERA-B will test CKM at the O(3) level.
• LHCb is a second generation experiment for CP violation studies in the B and Bs meson systems. The goal is to obtain precise and overconstrained determination of CKM elements, including terms beyond O(3). This will permit to detect deviations from the Standard Model description and thus to probe New Physics.
• Second generation means:
– High statistics is needed to study Bu,d,s decays with Br < 107
– Excellent proper time resolution
– Excellent particle identification
– Efficient and flexible triggering scheme, including a selection on hadrons.
• High statistics can be obtained by LHCb because
– B production cross section at 14 TeV:
– LHCb running luminosity:
fi
LHCb overlook
Rate(bb) = 105 sec1 : 0.5% total inelastic Rate(bb) = 105 sec1 : 0.5% total inelastic
bb ≈ 500 bbb ≈ 500 b
cm s cm s
LHCb
LHC beamscollide here
Magnetdipole
Vertex Locator
Œ[15, 300]mrad
Œ4.91.9
x
z
20 m10 m
Open geometry with (quite) easy access to (almost) all components
non-bendingplane view
Vertex Locator (VELO)
Design work on front-end chip (DMILL and sub-micron technolgies) in progressprototype of R measuring 1/2 plane
-20
80 cm
0
toward
spectrometer
retract by3 cm duringbeam setup
0 0.8 4 cm• ≈ 200 m Si single-side• R and measuring planes• 220 kchannels, analogue R/O, S/N =15
z ≈ 40 m resolution on
interaction point
Z
impact parameter
100
10
[m]
0.1 1 10Pt [GeV]
RICH
Threshold [GeV/ c ]
Aerogel C4F10 CF4
.6 .6 4.4K . 9. 5.6
K– separation > 3 1<p< 100 GeV/c
largeaerogelrings
smallC4F10 CF4 rings
pixel HPD
Gas CF4
Gas C4F10
Aerogel
pedestal
1 p.e.
2 p.e.
3 p.e.
4 p.e.
RICH R&D
DEP prototype pixel HPDDEP prototype pixel HPD
Photodetectors options:HPDs and multianode PMTs
• single photoelectron resolution•QE = 17% @ 400 nm• spatial resolution ~1 mm• large area ~2.9 m2, active: ~ 70% 325 kchan. binary readout• B stray field up to 100 gauss• radiation dose < 3kRad/year
Pion beam:large rings in aerogeland small rings in C4F10
threshold
Other Systems Magnet: Warm dipole 4 Tm - 4.2 MW - 1450t TDR ok Tracker
Inner: (40x60 cm2) triple GEM , Si 3 stations
Outer: straw-tube drift chambers p/p = 0.3 % [5 , 200] GeV/c
(MB) =15 MeV/c2
(MD) = 4 MeV/c2
Calorimeter (design completed)
Pre-shower sandwich Pb - scintillators
ECAL Shashlik type, 25 X0
HCAL Fe + scintillating tiles, 5.6R/O by wave-length shifting fibers and PMTs MUON
Resistive Plate Chambers (RPC) + Wire and Cathode Pad Chambers (WPC/CPC) for high rate regions
HCAL Fe+scintillating tiles
ECAL Shashlik
Joint Calorimeter Test
0 20 40 GeV
30
20
10
0
HCAL resolution %
0 50 100 150 200 GeV
preshowerECAL resolution %
LHCb Trigger Efficiency
L0(%) L1(%) L2(%) Total(%) e h all
BdJ/(ee)KS + tag 17 63 17 72 42 81 24BdJ/()KS + tag 87 6 16 88 50 81 36BsDsK + tag 15 9 45 54 56 92 28BdDK Bd + tag 14 8 70 76 48 83 30
for reconstructed andcorrectly tagged events
where the hadron trigger is important
where the leptontrigger is important
Tags considered (so far): – muon or electron from other b-hadron b lepton
– charged kaon from other b-hadron b c s
Overall tag efficiency = 40% Overall mistag rate = 30%
Tags considered (so far): – muon or electron from other b-hadron b lepton
– charged kaon from other b-hadron b c s
Overall tag efficiency = 40% Overall mistag rate = 30%
Trigger System
~30 %
~10%
Running luminosity
2 x 1032
Running luminosity
2 x 1032
LHC: 40 MHz L0:1 MHz L1:40 KHz Output:200 Hz
High PT electronsHigh PT hadrons
High PT muons
Pileup Veto
L0decision
unit
L1 Trigger3D reconstruction
of secondary vertices
L2+L3 TriggerFull event
information
Latency: 4 s < 2 ms
B0
Inelastic pp interactions
hadron triggerthreshold
DsK
Ds
5.2 5.3 5.4 5.5 GeV/c2
Mass, decay time resolutions and particle ID
Measurements of ms
with a significance >5: up to4psxs5
Bs-Bs oscillations with BsDs
ms 30 ps
Bs DsKseparation from
Bs Ds
Bs DsKseparation from
Bs Ds
DsK
Ds
5.2 5.3 5.4 5.5 5.6 GeV/c2
m = 11 MeV/c2m = 11 MeV/c2Mass(DsK)
with RICHwithout RICH
LHCb CP Sensitivities in 1 year
Parameter Channels+c.c. No of events (1 year)
Bd 5k @P/T = 30°, |P/T|=0.200.02, =90° 2-5
Bd0 1k @ =50° 5
2+ Bd D*(incl.) 260k @2+=0 12
BdJ/Ks 100k <0.6
-2 Bs DsK 2400 8(ms=15ps-1) - 12 (45ps-1)
Bd DK* 400 10
Bs J/ 50k 0.6
Bs oscillations
xs Bs Ds 35k up to 75 (5)
Rare Decays
Bs 11 s/b=3.5
Bd K0* 4500 s/b=16
Bd K* 26k s/b=1
See yellow Book CERN 2000-004 !
2000
2001
2002
2003
Inner Tracker
Vertex Detector
RICH, Calorimeters
Muon System
L0 & L1 Trigger, DAQ
Computing
Outer Tracker
Magnet installation
LHCb schedule (and conclusion)
2004
2005
Magnet
1998 Technical Proposal 1999 LHCb approved
LHCb ready for LHC « day one »and for many years of B physicsat “nominal LHCb luminosity”
TechnicalDesignReports
Detector and DAQ installation